During the late 1880s, a fierce debate broke out in the pages of the libertarian periodical Liberty over egoistic versus natural-rights approaches to anarchism. (The various contributions to this debate will eventually be available in the Molinari Institute's online library ; in the meantime, for details see Frank H. Brooks' The Individualist Anarchists: An Anthology of Liberty (1881-1908)  or Wendy McElroy's The Debates of Liberty: An Overview of Individualist Anarchism, 1881-1908 .) The egoists argued that there could be no rational grounds for any person to recognise any authority above her own reason or to place any goal before her own happiness. Hence they rejected 'morality' as metaphysical mumbo-jumbo, concluding that no one has any reason to accept any principles of conduct, anarchist or otherwise, except insofar as accepting those principles is strategically effective in promoting one's own interests. The consistent anarchist, they insisted, should accept no unchosen constraints, moral or political, on her own sovereign will. The natural-rights proponents argued that respect for the inviolability of other people's rights is a sine qua non of anarchism. Even if the egoist respects anarchist boundaries in practice ' something of which the natural-rightsers felt none too confident ' she must nonetheless reserve in principle an entitlement to impose her will on others should she judge doing so to be in her own interest. Hence the egoist must regard others' freedom as a revocable gift from herself to them, rather than an inherent right; but this is to take the attitude of a ruler to her subjects, not of an anarchist to her peers. The consistent anarchist, the natural-rightsers argued, must reject egoism in favour of a universal and binding moral law. I've long held that Greek philosophy and modern libertarianism are natural allies, tailor-made for each other ' not because they are similar but because through their very differences each can supply the deficiencies of the other. This debate in Liberty is another example. Both sides of this debate shared a common assumption: that respect for others' rights is not itself a component of our self-interest. From this assumption it follows that one must choose between putting one's own interests first and regarding other people's rights as having intrinsic weight. But this is precisely what is challenged by Classical Eudaimonism, the moral theory pioneered by Socrates, developed in different ways by Plato, Aristotle, and the Stoics, and accepted by nearly every major moral philosopher before the Renaissance, including Cicero and Thomas Aquinas. According to Classical Eudaimonism, self-interest is indeed the ultimate criterion of right action, but our true self-interest is to live a life of objective human flourishing. Acting in accordance with the virtue of justice is not a mere external means to such flourishing, it is part of that flourishing; hence self-interest properly understood requires that we place value ' and not merely strategic value either ' on behaving justly toward others. Hence the Classical Eudaimonist can happily embrace both the egoist's insistence of the paramount supremacy of self-concern and the natural-rightser's insistence on the sacred authority of justice. I may be asked: 'Well, it's nice that Classical Eudaimonism can reconcile the two sides of this debate, but why should we believe that Classical Eudaimonism is true?' My answer is that the fact that Classical Eudaimonism can reconcile the two sides of the Liberty debate is itself an extremely good reason for thinking it's true. (In saying this I'm relying on a Greek-style coherentist moral epistemology that I won't spend time defending here; but see my article The Basis of Natural Law , my book Reason and Value: Aristotle versus Rand , and my review of Leland Yeager's Ethics As Social Science .) Of course, the Classical Eudaimonists' views on the content of justice generally bore little resemblance to individualist anarchism. But that's why the ideas of the Greek philosophers require as much correction from libertarian ideas as libertarian ideas require correction from the Greeks. Symbiosis, man.